To increase user capacity of the system, existing radio communication networks usually adopt low frequency reuse factor, i.e., all the cells share the same time-frequency resources. However, inter-cell interferences caused by low frequency reuse factor are an important factor restricting downlink capacity. For a mobile terminal which is located at a cell edge (i.e., the area between neighboring cells), while receiving useful signals from the base station to which the mobile terminal pertains, it also receives signals transmitted by other base stations with the same time-frequency resources. And the signals from the other base stations constitute interferences to the mobile terminal.
In order to improve user performance at a cell edge without a loss of (or with an increase in) overall cell throughput, the applicant of the present invention has provided a multi-cell multiple input multiple output (multi-cell MIMO) technology.
Multi-cell MIMO is a technology family and has been proposed as a candidate technical solution for the Long Term Evolution (LTE) project and IEEE 802.16m. In multi-cell MIMO technology, a mobile terminal located at the collaboration area can be served by multiple base stations. By closely coordinating data transmission and reception of multiple base stations, multi-cell MIMO technology changes inter-cell interferences to useful signals, thereby breaking through the restriction from frequency spectrum efficiency in conventional cellular systems.
However, it should be noticed that, in a real-time system, information exchange in the backhaul network caused by multi-cell MIMO technology is a great overhead and results in problems such as additional delay.
Technical solutions of multi-cell MIO include technical solutions of centralized multi-cell MIMO, such as a network MIMO solution, which have high computational complexity.
Technical solutions of multi-cell MIMO also include technical solutions of distributed multi-cell MIMO, such as a collaborative MIMO solution. In multi-cell scheduling, it is still a great challenge to better define the collaboration strategy between neighboring cells, which directly affects the system gain of a distributed multi-cell MIMO system.